Boston_to_a_T tweeted the explosion at the Boston Marathon 2013 finish line. A suspicious figure is outlined in red. (Photo: Twitter / Boston_to_a_T)

Who was the mystery man on the roof when the bombs detonated at the Boston Marathon finish line on Monday?

The original image was snapped by spectator Dan Lampariello, capturing the explosion of the second bomb at the Boston Marathon finish line. First posted on his @Boston_to_a_T Twitter account Monday afternoon, the image has since been re-tweeted more than 2000 times. It would only be a matter of time before someone would notice a mystery man on the roof.

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Explosion at coply twitter.com/Boston_to_a_T/…

— Boston to a T (@Boston_to_a_T) April 15, 2013

The discovery sparked overwhelming reactions through the social network, as Boston authorities had yet to confirm the custody of any suspicious individuals.

While it may be nothing, I'm still confused as to how this mystery man on the roof hasn't been given more media attention. #PrayersForBoston — Sam McClure (@sam_mcclure) April 16, 2013

I wonder if the FBI could look at cameras from that building to find the guy on the roof in the top left ... #Boston twitter.com/STEF_aside_btc… — Stefani Karavasilis (@STEF_aside_btch) April 16, 2013

Hold up, FBI... No need to continue investigations: the Sun has found the Boston bomber (via@iburrell)thesun.co.uk/sol/homepage/n… — Guy Adams (@guyadams) April 16, 2013

While the majority of Twitter users readily admit that the mystery man cannot simply be guilty for taking a walk along the roof top, the troubling images indicate the mystery man on the roof exhibiting no reaction to the ground-shaking shockwave. Did he expect the blast to occur? Is he responsible for the attack?

Police Commissioner Ed Davis announced that the Boston Police has yet to bring any person-of-interest into custody during the Monday evening press conference, UPI reported. What's more, FBI Special Agent RichardDesLauriers confirms that preliminary investigations point the explosions towards terrorist activity.

"I encourage everyone to have a heightened state of vigilance in the Boston area." said DesLauriers. Authorities stated that no specific evidence of a bomb threat were found prior to the incident.

Two explosions occurred at the Boston Marathon finish line area, near downtown's Copley Square. The bombs were detonated just before 3 p.m. A second incendiary explosion followed later that afternoon at the JFK Library. Boston authorities have yet to confirm whether the two explosions were linked.

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